Why multiple cameras are mounted on the same traffic pole?

If these cameras are for traffic monitoring or recording violations for fines, why are so many needed? Is there another purpose? I hope to hear experts provide insight on this.

Multiple cameras installed on a traffic pole on a street in Hanoi. Photo from Facebook

Vu Manh Gioi, Business Development Manager at Dahua Vietnam, a provider of high-tech security equipment, said at certain intersections, particularly in urban areas and central districts of large cities, it is common to see multiple cameras mounted on a single pole.

These cameras are not only used for traffic monitoring or collecting evidence for traffic fines; they may also belong to various government agencies, Gioi said.

These cameras may serve multiple functions, including security operations by district police, protection for state and international delegations, flood monitoring by drainage companies, and even live broadcasts by VOV Traffic radio station.

For traffic monitoring specifically, several cameras may be installed on the same pole, each with a specialized purpose.

These include large speed-detection cameras, lane-specific surveillance cameras (particularly on roads with multiple lanes), and cameras that analyze traffic density.

As technology advances, modern traffic cameras can now perform multiple functions within a single system, reducing the need for so many individual cameras.

However, transitioning to such a setup comes with significant costs, and many cities continue to use existing infrastructure. Typically, newly installed intersections will have fewer cameras but with improved quality compared to earlier installations.